1. Field of the Invention.
This invention relates generally to sorbent material broadcasters and more particularly to such sorbent material broadcasters that are capable of distributing sorbent materials at a controlled rate uniformly over an oil slick.
2. Description of the Prior Art.
Spills of liquid hydrocarbon compounds such as petroleum crude oil, fuel oil and the like present a serious water pollution problem and various means have been proposed to quickly remove such spills before contamination of the sea bottom and adjacent shoreline occurs. Such spills occur both in protected waters such as harbors and also occur in offshore or unprotected waters. Spills in harbors result principally from oil transfer operations, industrial waste discharges, pipeline breaks, collisions and the like, and generally amount to volumes in the order of 100 barrels. Spills in offshore waters normally result from collisions or grounding of tankers in merchant vessels or as a result of malfunction of an offshore oil rig. Although less frequent, such offshore spills are often very large. The offshore type of oil spill is particularly difficult to deal with because of the wave action which interferes both with efficient consolidation or confinement of the oil slick to a small area and also with the mechanical separation of the oil from the water's surface.
Various means have been employed in an effort to clean up spilled oil including the use of chemicals to cause sinking or dispersion of the oil and the distribution of absorbent materials on the surface of the slick. In addition, burning of the slick has been attempted as well as skimming of the surface oil by means of rotating cylinders, suction devices, and the like.
Chemically caused sinking or dispersion of the oil pollutes the water in the harbor or sea bottom. Burning or incineration is objectionable because of atmospheric pollution and because of the difficulty in maintaining the oil slick at a temperature high enough to sustain combustion. The skimming process which is capable of removing relatively large quantities of oil at a comparative high rate undesirably requires large and expensive settling or centrifuging devices which depend for efficient operation upon a relatively precise orientation of the weir or other skimming device relative to the thickness of the surface film of oil. Wave action in unprotected waters makes the skimming process very impractical.
The distribution of sorbent materials on the surface of the oil slick by mechanical broadcasting followed by the harvesting and regenerating of the oil sorbent material is a most effective and efficient method of removing an oil slick from the water surface. However, uniform mechanical broadcasting of sorbent material has proved to be extremely difficult with present devices. Prior art sorbent material broadcasting devices have been limited to the pneumatic type where the sorbent material in the form of pieces such as cubes, chips or chunks is blown out of a nozzle and dispersed onto the water surface therefrom. However, such pneumatic devices are highly affected by winds which alter the landing location of the sorbent material. It is extremely difficult to get uniformity of dispersion and controllability of the drop rate of the sorbent material from such pneumatic devices.